1. Field of the Invention
The present invention relates to a cutting apparatus, and more particularly, to an apparatus for cutting liquid crystal display panels and a cutting method using the same. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for substantially reducing a process time in fabricating a liquid crystal display panel.
2. Discussion of the Related Art
A liquid crystal display device provides liquid crystal cells arranged in a matrix form with corresponding data signals according to image information in order to display a desired image by controlling light-transmittance of each liquid crystal cell. In order to improve yield, a method of fabricating the liquid crystal display device includes the steps of forming thin film transistor array substrates on a large mother substrate, forming color filter substrates on another mother substrate, bonding the two mother substrates to each other to form a plurality of liquid crystal display panels at the same time. Hence, the method demands a process of cutting the bonded mother substrates into unit liquid crystal display panels.
Such a cutting process of the unit panels generally includes forming a scribing line on a mother substrate by using a diamond pen having hardness greater than that of glass, and cutting the substrate by applying a mechanical force thereto. Such a cutting process of the unit panels will now be explained in detail by referring to the attached drawings as follows.
FIG. 1 illustrates a schematic layout of a related art unit liquid crystal display panel prepared by bonding a thin film transistor array substrate and a color filter substrate to each other.
Referring to FIG. 1, a liquid crystal display panel 10 includes an image display part 13 having liquid crystal cells arranged in a matrix form, a gate pad part 14 connected to gate lines of the image display part 13, and a data pad part 15 connected to data lines. In this case, the gate and data pad parts 14 and 15 are respectively formed on the edge areas of a thin film transistor array substrate 1 which does not overlap a color filter substrate 2. The gate pad part 14 provides the gate lines of the image display part 13 with each corresponding scan signal supplied from a gate driver integrated circuit, and the data pad part 15 provides the data lines with image information supplied from a data driver integrated circuit.
On the thin film transistor array substrate 1 of the image display unit 13, the data lines having the image information applied thereto and the gate lines having the scan signals applied thereto are arranged to vertically cross each other. Thin film transistors at each intersection are formed to switch the liquid crystal cells. Pixel electrodes are connected to the thin film transistors to drive the liquid crystal cells. A passivation layer is formed on the entire surface to protect the electrodes and the thin film transistors.
Moreover, color filters separated by a black matrix for each cell area are formed on the color filter substrate 2. A transparent common electrode as a counter electrode of the pixel electrode is formed on the thin film transistor array substrate 1.
A cell gap is provided between the thin film array substrate 1 and the color filter substrate 2, which are bonded to each other by a sealing part (not shown) formed at the periphery of the image display unit 13, so as to be spaced apart from each other. A liquid crystal layer (not shown) is formed in the space between the thin film transistor array substrate 1 and the color filter substrate 2.
FIG. 2 illustrates a cross-sectional view of a first mother substrate having thin film transistor array substrates 1 and a second mother substrate having color filter substrates 2, wherein the first and second mother substrates are bonded to each other to form a plurality of liquid crystal display panels.
Referring to FIG. 2, each unit liquid crystal display panel has a thin film transistor array substrate longer than a corresponding color filter substrate 2. This is because the gate and data pad parts 14 and 15 are formed at the corresponding edges of the thin film transistor array substrate 1 which does not overlap the color filter substrate 2, as shown in FIG. 1.
Hence, the second mother substrate 30 and the color filter substrates 2 formed thereon are spaced apart from each other by a dummy area 31 corresponding to the protruding area of each thin film transistor array substrate 1 on the first mother substrate 20.
Moreover, the unit liquid crystal display panels are arranged so as to maximize the use of the first and second mother substrates 20 and 30. Although it depends on models, the unit liquid crystal display panel is generally spaced apart from each other at a distance corresponding to the area of the other dummy area 32.
After the first mother substrate 20 having the thin film transistor array substrates 1 is bonded to the second mother substrate 30 having the color filter substrates 2, a scribing process and a breaking process are carried out to individually cut the liquid crystal display panels. In this case, the dummy area 31 formed between each color filter substrate 2 of the second mother substrate 30 and the other dummy area 32 formed between each unit liquid crystal display panel are removed at the same time.
The related art cutting process of the unit liquid crystal display panels is explained in detail by referring to FIGS. 3A to 3J as follows.
Referring to FIG. 3A, first and second mother substrates 20 and 30 bonded to each other are loaded on a first table 33.
In FIG. 3B, the first table 33 moves in one direction to a previously set distance to sequentially form a first scribing line 42 on the first mother substrate 20 through a cutting wheel 41.
Referring to FIG. 3C, the first and second mother substrates 20 and 30 are turned by 90xc2x0. The first table 33 moves back to its initial location at the previously set distance to sequentially form a second scribing line 43 on a surface of the first mother substrate 20 through the cutting wheel 41.
As shown in FIG. 3D, the first and second mother substrates 20 and 30 are overturned and are loaded on a second table 34. The second table 34 moves in one direction at a previously set distance, and propagates a crack on the first mother substrate 20 by pressing the second mother substrate 30 with a breaking rod 44 along the second scribing line 43.
As shown in FIG. 3E, after the second and first mother substrates 30 and 20 are turned by 90xc2x0, the second table 34 moves back to its initial location at the previously set distance, and propagates a crack on the first mother substrate 20 by pressing the second mother substrate 30 along the first scribing line 42 with the breaking rod 44.
As shown in FIG. 3F, after the second and first mother substrates 30 and 20 are loaded on a third table 35, the third table 35 moves in one direction at a previously set distance to sequentially form a third scribing line 46 on the surface of the second mother substrate 30 through a cutting wheel 45.
Referring to FIG. 3G, the second and first mother substrates 30 and 20 are turned by 90xc2x0, and the third table 35 moves back to its initial location at the previously set distance to form a fourth scribing line 47 on the surface of the second mother substrate 30 through the cutting wheel 45.
As shown in FIG. 3H, the second and first mother substrates 30 and 20 are overturned to be loaded on a fourth table 36. The fourth table 36 moves in one direction at a previously set distance and propagates a crack on the second mother substrate 30 by pressing the first mother substrate 20 with a breaking rod 48 along the fourth scribing line 47.
In FIG. 3I, after the first and second mother substrates 20 and 30 are turned by 90xc2x0, the fourth table 36 moves back to its initial location at the previously set distance and propagates a crack on the second mother substrate 30 by pressing the first mother substrate 20 along the third scribing line 46 with the breaking rod 48.
Referring to FIG. 3J, the first and second mother substrates 20 and 30 are cut into unit liquid crystal display panels as the cracks are propagated along the first to fourth scribing lines 42, 43, 46, and 47 on the first and second mother substrates 20 and 30. The unit liquid crystal display panels are selectively unloaded using a suction plate 49 to be transferred to equipments for a following process.
However, the related art apparatus and method for cutting the liquid crystal display panels turn the first and second mother substrates four times and overturn the first and second mother substrates twice, whereby the apparatus becomes complicated, and the method takes too much time for the scribing, breaking, turning, and overturning steps.
Accordingly, the present invention is directed to an apparatus for cutting liquid crystal display device panels and a cutting method using the same that substantially obviate one or more of problems due to limitations and disadvantages of the related art.
Another object of the present invention is to provide an apparatus for cutting liquid crystal display panels and a cutting method using the same to minimize a processing time taken for cutting the first and second mother substrates into unit liquid crystal display panels.
Additional features and advantages of the invention will be set forth in the description which follows and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, an apparatus for cutting liquid crystal display panels includes a first scribing unit sequentially forming a plurality of first scribing lines on surfaces of first and second mother substrates having unit liquid crystal display panels and cutting the first and second mother substrates along the first scribing lines, a first turning unit turning the cut first and second mother substrates by 90xc2x0, and at least two second scribing units sequentially forming a plurality of second scribing lines on the surfaces of the first and second mother substrates and cutting the first and second mother substrates along the second scribing lines.
In another aspect of the present invention, a method for cutting liquid crystal display panels includes sequentially forming a plurality of first scribing lines on surfaces of first and second mother substrates having unit liquid crystal display panels, cutting the first and second mother substrates along the first scribing lines, turning the cut first and second mother substrates by 90xc2x0, forming a plurality of second scribing lines on the surfaces of the first and second mother substrates, and cutting the first and second mother substrates along the second scribing lines.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.